Preparation and characterization of a novel silica fluorescent nanoparticles with DPPDA-Eu3+ doped

A new ligand of 4,7-diphenyl-1,10-phenanthroline-2,9-dicarboxylic acid (DPPDA) and Eu³⁺chelate compound of this ligand were prepared. Then DPPDA-Eu³⁺ doped silica fluorescent nanoparticles of DPPDA-Eu³⁺/SiO² with primary amino groups on their surface were developed using a water-in-oil (W/O) microemulsion technique. Characterizations by transmission electron microscopy, fluorescent spectra, fluorescent molecules leaking experiments and photostable experiments show that the nanoparticles are spherical and uniform in size of 80 ± 8 nm, monodisperse, highly fluorescent signal and highly photostability. No obvious of fluorescent molecules leaking was observed. The nanoparticle as a novel fluorescent probe is expected to be applied in highly sensitive bioassays such as time-resolved fluorescence, biosensor and biochip.